Linn LP12 History and Upgrade path

Posted May 3rd, 2002 by JaS

The following information was compiled from an official Linn customer services document.

The LP12 has had many upgrades through the years. The major ones were given exotic names, like Nirvana, Valhalla, Lingo, Trampolin reflecting the advances in accurate sound reproduction which they represented. There have also been many unnamed improvements like new feet, new baseboard, new armboard, new suspension springs and grommets and new plinth. The list is long and it means that an LP12 need never be out of date.

Cirkus Kit

The Cirkus upgrade to the LP12 focuses on bearing performance and the connection of the bearing housing to the sub-chassis. The improved bearing and stronger sub-chassis arrangement provides the turntable with greater stability and ensures the bearing sits perfectly true to the chassis of the turntable. This in turn minimises the risk of turntable platter movement with respect to the sub-chassis and arm. Even the slightest movement will introduce audible degradation to the reproduced signal.

Together the changes to the bearing and the sub-chassis make an enormous difference to the overall performance of the turntable. The specific changes are as follows :

The thickness of the bearing housing mounting flange has been substantially increased and undercuts eliminated to make it many times more rigid. This also allows the use of larger mounting bolts.

Increased distance between top and bottom liners in the bearing housing to make it as stable as possible eliminating even the smallest amount of rocking

An increase in the height of the bearing housing from the top of its inner liner to increase oil capacity, ensuring proper lubrication of the top bearing at all times

Double thickness sub-chassis to improve rigidity, reducing flexing and improving control of the relationship between key components

The attached kit of parts, which includes a new inner platter and spindle, is supplied to fit this upgrade. As always with Linn product improvements, new LP12 turntables will incorporate this upgrade as standard.

All Linn products are subject to continuous development programmes and we aim to make similar advances in sound quality in future as we have in the past.

Lingo Power Supply

Date Introduced: 1990 The Linn Lingo is a high precision, direct coupled, power supply designed to sit alongside the LP12 turntable. The Lingo upgrade moves the LP12's performance into a new league, further distancing it from the competition.

At the heart of the Lingo are two very low noise crystal oscillators derived from the Linn Numerik digital studio recording system - one for 33.33 rpm and one for 45 rpm. The switch on the turntable selects the appropriate oscillator, the output of which is fed into a synchronous counter to produce a 50 Hz or 67.5 Hz square wave for 33 rpm and 45 rpm respectively.

As the LP12 motor runs at its quietest when driven with a clean sinusoidal waveform, a precision filter is employed in the Lingo to remove harmonics from the square wave leaving only a pure wave form.

The most uniform torque is delivered from the motor when both phases are driven at ninety degrees with respect to one another. This is achieved by a ninety degree phase-shift network after the filter. The two resulting sinusoids drive two high voltage class A amplifiers, the outputs of which drive the two motor windings.

The Lingo uses 'stall detection' circuitry to feed the motor with a higher voltage for increased start-up torque. When the platter reaches the selected speed, this load-sensing circuitry reduces the power output. From then on the motor just maintains the platter's own inertia to keep it going silently.

A toroidal transformer on the PCB, and a mains filter, give a very high degree of electrical isolation from the mains voltage supply.